Proteomics Profiles of CD34⁺ Cells in Bone Marrow of Patients with Severe Aplastic Anemia

Objective

Application of isobaric tags for relative and absolute quantification (iTRAQ) technology, the proteins of CD34⁺ cells in bone marrow for patients with severe aplastic anemia (SAA) and normal controls were analyzed. To obtain differential proteomics profiles of CD34⁺ cells in bone marrow for SAA specificity. To preliminary screen the autoantigen which may cause immune system hyperfunction in SAA, providing a theoretical basis for further elucidating the immune pathogenesis of SAA.

Methods

Untreated SAA patients, remission SAA patients, as well as normal controls in Tianjin Medical University General Hospital from 2013.1 to 2014.2 were enrolled in this study. CD34+ cells in bone marrow for 29 cases of recovery SAA patients and 10 normal human were purified by immunomagnetic cell sorting, total protein were extracted and were processed enzymolysis, labeled sample by iTRAQ reagent, then analyzed the protein of sample by multidimensional liquid chromatography tandem mass spectrometry of Q Exactive, identified proteins by application of database, compared the different expression of proteins between SAA patients and normal controls, to preliminary screen the autoantigen which may cause immune system hyperfunction in SAA.

Results

Expression of differential proteomic profiles for CD34+ cells in SAA bone marrow were obtained. The protein confidence > 95% and identification of peptide protein false positive rate < 1% were limited, 15120 peptides and 3208 protein were identified. The Ratio of different proteins (SAA group/ normal group) greater than 2.794 and less than 0.323 and the confidence limit greater than 95% were limited , 157 different proteins with high confidence were identified, of which 54 up-regulated proteins, 103 down regulated proteins. The physiological function of proteins involved cell apoptosis, cell cycle, RNA splicing and metabolism, protein modification and transfer, the ubiquitin proteasome mediated protein degradation.

Conclusions

The proteome profiles of CD34+ cells in SAA bone marrow were obtained successfully, and it was proved that iTRAQ marker tandem mass spectrometry for proteome of bone marrow cells for patients with SAA was an effective method. It was found that 157 abnormal expression proteins of CD34+ cells in SAA bone marrow, the function of proteins mainly involved apoptosis, cell cycle, protein modification and transport, RNA processing and splicing, the ubiquitin proteasome system. We preliminary predicted autoantigen which may cause SAA immune "waterfall" activation.